Swiss drugmaker Roche Holding AG would not exclude a move into treatments for rare diseases, its CEO said on Wednesday, even if this represented very small numbers of patients. Chief executive Severin Schwan told a news conference in Paris that Roche's main criteria in terms of disease was not the size of the patient population but how much additional value and medical benefit could be generated for the individual patient. Asked if that meant he did not exclude a move into rare diseases, he said: "We go where the science takes us, wherever it is, independent from the size of the patient population."